Ascaridoid nematodes in horse mackerel, Trachurus trachurus, sold in Spanish supermarkets¿Factors able to diminish consumer risk

Horse mackerel, Trachurus trachurus, specimens sold in supermarket chains in the metropolitan area of València (Spain) were analyzed to assess which intrinsic and extrinsic factors are able to diminish the risk of human anisakiosis. 202 T. trachurus, caught in the Atlantic Ocean and the Mediterranean Sea, were examined for as- caridoid nematodes. The overall prevalence and abundance of Anisakis type I larvae were 65.3 % and 23.2 helminths/host, respectively, being higher in the Atlantic area (98.2 %; 41.4 helminths/host). 34.2 % of the total fish sample was parasitized in the flesh. Moreover, global prevalence and abundance of Hysterothylacium spp. larvae were 67.3 % and 9.41, respectively, with only 5.9 % of fish parasitized in the flesh, and all larvae were found dead after artificial digestion, suggesting a very low risk of infection. In the case of Anisakis type I, a positive correlation between host body size and parasitic burden was found. T. trachurus should be considered a potential source of anisakiosis infection in Spain. However, given the high prevalence of Hysterothylacium, al- though not being considered a real human hazard, consumers should be warned about its presence, as they are not able to differentiate between this genus and Anisakis or other ascaridoid nematodes, and can thus be induced to discard the fish infested with Hysterothylacium. The risk of infection by Anisakis can be minimized following the measures established by Spanish and European Union legislation, with the consumption of fresh eviscerated fish, preferably small-sized specimens caught in the Mediterranean, or avoiding small-sized specimens from the Atlantic.
Bibliographic reference
Debenedetti, Á. L., Codes, F., Laza, S., Hernández, S., Madrid, E., Trelis, M., & Fuentes, M. V. (2020). Ascaridoid nematodes in horse mackerel, Trachurus trachurus, sold in Spanish supermarkets—Factors able to diminish consumer risk. En Fisheries Research (Vol. 230, p. 105669). Elsevier BV.